Apparatus for controlling highway crossing signals



Patented Apr. 3, 1951 APPARATUS FOR CONTROLLING HIGHWAY CROSSING SIGNALS Myrl R. Douglass, Edgewood, Pa, assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application May 18, 1948, Serial No. 27,637

7 Claims.

My invention relates to apparatus. for controlling highway crossing signals, and particularly to apparatus for starting the operation of a highway crossing signal when a train arrives at a point, the distance of which, fromthe intersection of a railway and a highway, is'determine'd according to the speed of the approachi'n'gtrain.

It is important that a highway crossing signal be operated long enough before the arrival of a train at the intersection of a railway and a highway to provide ample warning to users of the highway that a train is approaching, so that users of the highway will have sufficient time to get in the clear. It is, however, desirable that a highway crossing signal be not operated so long before the arrival of a train at the intersection as to unduly delay users of the highway and thereby cause them to become careless about obeying the indications given by highway crossing signals. we

In order to provide periods of operation of a highway crossing signal which are or" about the same duration or are within given limits of duration for trains approaching at difierent speeds, it is necessary that operation of the highway crossing signal be initiated when trains moving at low speeds are closer to the intersection than when trains are moving at higher speeds.

One feature of my invention is therefore the provision of novel and improved apparatus for starting the operation of a highway crossing signal when a train arrives at a point, the distance of which, from the intersection of a railway and a highway, is determined according to the speed at which the train is approaching the intersection.

I shall describe one form of apparatus cmbodying my invention, and shall then point out the novel features thereof in claims.

In the accompanying drawings, Fig. l is a diagrammatic view showing one form of apparatus embodying my invention, in'which a railway which intersects a highway, is divided into a timing section and an operating section arranged so that a train approaching the intersection occupies first the timing section, and then the operating section; and in which the speed of a train moving over the timing section is measured by a plurality of time element devices; and also in which operation of the highway crossing signal started when a train arrives at a point the operating section which is determined according to the speed at which the train moves over the timing section; and Fig. 2 ma diagrammatic view showing a modification of a portion of the apparatus of Fig. 1. 1

Similar reference characters refer to similar vices are identified by numbers, each such hum-n her have a distinguishing prefix from which it is separated by a dash when the associated'contact is shown apart from the relay by which it. is operated. The prefix for each of these contact numbers comprises the reference character for the respective relay by which the associated contact is operated. For example, contact CRP-ZZ, shown in Fig. 2, in the energizing circuit for time element device ZD'E, is identified by the number 22 separated by a dash from the prefix CRP which is the reference character for relay CRP' by which this contact is operated.

Referring first to Fig. 1 of the drawings, a stretch of railway track is shown intersected by a highway H. Rails I and la of the track are divided by insulated joints 2 to form a timing section '1 and an operating section C arranged so that a train approaching the intersection in the direction indicated by the arrow, which I shall assume is the eastbound direction, moves first over the timing section T, and then over the operating section (3'.

With apparatus embodying my invention, the speed at which a train moves over section T is measured by time element means, and the operation of the highway crossing signal is then started when the train reaches a point on section C from which a given minimum time will be required for the train to travel at the measured speed to the intersection of the railway and the highway. A minimum time of 20 seconds has been assumed for this purpose, although some other time might be used.

For purposes of illustration, I have assumed a maximum train speed of miles per hour, and have shown section T to be 880 feet long, which is the'distancea train traveling at that speed will go in 5 seconds. I have also shown section C to be 3700 feet long, which is the distance a train traveling at that speed will go in 21 seconds.

Each of the sections T and C is provided with a track circuit including a suitable source of current, such as a battery 3, connected across the rails adjacent one end of the section, and a track relay, designated by the reference character R preceded by the reference character for the associated section, connected across the rails adjacent the opposite end of the section.

The'speed at which an eastbound train, while approaching highway H, moves over section T, is.

measured by three time element devices, the first of which is designated. by the reference character ITE, the second of which is designated by the reference character 2TE, and the third of which is designated by the reference character Each of these time element devices has a normally open contact I3 which becomes closed upon the lapse of a measured period of time after its time element device becomes energized in response to a train entering section T. As indicated by the legend on the drawing adjacent the symbol for each of the time element devices, these devices are constructed so that contact I3 of device ITE becomes closed upon the lapse of 5 seconds after the device ITE becomes energized, contact it of device ZTE becomes closed upon the lapse of 7 /2 seconds after device ZTE becomes energized, and contact E3 of device 3TE becomes closed upon the lapse of 10 seconds after device 3TE becomes energized. These time element devices may be of any suitable design such, for example, as the thermal type as shown in the drawings.

Associated with time element devices ITE, ZTE, and STE are timing stick relays designated by the reference characters lTES, ETES, and 3TES, respectively. Each of the relays iTES, ZTES, and STES has a pickup circuit which is closed by contact I3 of the associated time element device. Relay ITES, therefore, becomes energized when a train has occupied section T for a period of 5 seconds while traveling at a speed of 80 to 129 miles per hour, relay ZTES becomes energized when a train has occupied section T for a period of "1%,; seconds while traveling at a speed of 60 to 80 miles per hour, and relay STES becomes energized when a train has occupied section T for a period of 10 seconds while traveling at a speed less than 60 miles per hour. Each of the relays ITES, 2TES, and 3TES, upon becoming energized, opens a back contact H in a control circuit for the associated time element device, thereby deenergizing the time element device.

Signal stick relays, designated by the reference characters IDS, EDS, and 3DS are associated with timing stick relays ITES, ZTES, and ESTES, respectively.

A slow release relay, designated by the reference character CP, is controlled by track relay CR. A second slow release relay, designated by the reference character CRP, is in turn controlled by a front contact of relay CP. A resistor r is connected in multiple with the winding of each of the relays CP and CRP. The parts may be so proportioned that a time period of 1 sec- 0nd will elapse between the opening of contact 4 of relay CR and the releasing of the contacts of relay CRP.

A fourth time element device ZDE, and a fifth time element device SDE are controlled by back contacts of relay CRP. Each of the time element devices ZDE and EDE has a normally open contact 2 3 which becomes closed after the time element device has been energized a measured period of time. Time element devices 2DE and are constructed so that contact 24 of device ZDE be comes closed after device ZDE has been energized for a period of 10 seconds, and contact 24 of devioe 3DE becomes closed after device SDE has been energized for a period of seconds. Time element devices ZDE and 3DE may be of any suitable design such, for example, as the thermal type as shown in the drawing.

A first delay relay, designated by the reference character ID, is controlled. by a back contact of relay CRP. Second and third delay relays 2D and 3D are controlled by contact 24 of time element devices ZDE and 3DE, respectively.

Each of the signal stick relays IDS, 2DS, and EDS has a pickup circuit which is controlled by a front contact of the associated timing stick relay and by a front contact of relay CP. Each of the signal stick relays has also a stick circuit which is controlled by a back contact of an associated delay relay.

A highway crossing signal, designated by the reference character G, is controlled by a crossing relay which may be of the well-known interlocking type shown in the drawing, and designated by the reference character KX. Relay KX has a winding CX for eastbound traffic movements, and a second winding X for west bound trafiic movements. Winding CX is controlled by signal stick relays IDS, ZDS, and 3DS, and by track relay CR, so that if any one of the relays DS, vEDS, and SDS is energized when a train enters section C, winding UK will be retained in the energized condition for a period of time although relay CR is deenergized and its contact CR-l' is open. When all of the relays iDS, ZDS, and SDS are deenergized while relay OR is also deenergized, winding CX becomes deenergized, causing signal G to be operated by a circuit controlled by a back contact for winding CX of relay KX. Signal G may be of the flashing light type or of any other suitable design, such, for example, as a crossing bell as shown in Fig. 1 of the accompanying drawings.

Winding X of relay KX may be controlled by westbound traflic movements similarly to the manner just described, in which winding CX is controlled by eastbound traffic movements.

Referring now to Fig. 2, a delay stick relay, designated by the reference character ZDES, is here used instead of delay relay 2D shown in Fig. 1. Time element device ZDE is here controlled by a back contact of relay ZDES as well as by back contact CRP-ZZ. Relay ZDES has a pickup circuit which is the same as the energizing circuit for relay 2D, shown in Fig. 1. Relay ZDES has a stick circuit controlled by contact CRP-22. A delay stick relay 3DES may be similarly substituted for delay relay 3D shown in Fig. 1, and relay 3DES may have a pickup and a stick circuit similar to those shown for relay ZDES in Fig. 2.

With the parts of the apparatus proportioned as previously described and as shown in the drawings, relay IDS controls signal G to be operated for a period of from 20 to 29 seconds if a train moves over section T at a speed between and miles per hour; relay 2DS controls the operation of signal G for trains moving over section T at a speed between 60 and 80 miles per hour; and relay EDS controls operation of signal G for train speeds below 60 miles per hour.

Having described, in general, the arrangement and control of the apparatus shown by the accompanying drawings, I shall now describe, in detail, its operation.

As shown in the drawings, all parts of the apparatus are in their normal condition, that is, sections T and C are unoccupied, and therefore track relays TR and CR are energized; relays CP, CRP, and KX are energized; and relays I TES, ZTES, 3TES, ED, 2D, 3D, lDS, ZDS, SDS, and ZDES, time element devices iTE, ZTE, STE, ZDE, and 313E, and signal G are deenergized.

The circuit by which relay CP is energized passes from terminal B of a suitable source of current, through contact 4 of relay CR, and the winding of relay CP in multiple with a resistor r Z to terminal N of the same source of current. Relay CRP is energized by a similar circuitwhich includes contact 5 of relay (JP.-

Winding CX of relay KX is energized by a circuit passing from terminal B, through the back point of a contact 6 of each of the relays iDS, ZDS, and SDS in multiple with each other, contact CRri, and winding OK to terminal N.

I shall assume that, with apparatus as shown in Fig, 1, an eastbound train enters section T, deenergizing relay TR. Time element device ITE, therefore, becomes energized by a circuit passing from terminal B, through contact 8 of relay TR, contact II of relayv I TES, and the control element of device I TE toterminal N. Time element devices 2TE and 3TB also become energized by circuits which are similar to the circuit just traced for time element device ITE, and which are con trolled by back contacts of relay TR and by back contacts of relay ZTES and STES, respectively.

I shall assume further that the train moves over section T at a speed of 120 miles per hour, so that time element device STE closes its contact I3 just as the'train enters section C. Relay iTES, therefore, becomes energized by its pickup circuit passing from terminal 38, through contact I3 of time element device iTE, and the winding of relay !TES to terminal N. Relay l'lES, upon becoming energized, completes its own stick circuit passing from terminal B, through contact 8 of relay TR, contact Id of relay iTES, and the winding of relay ITES to terminal N.

Since relay CP is slow releasing, its contact I6 does not at once open when relay CP becomes deenergized on account of relay CR becomin deenergized. Relay iDS, therefore, becomes energized by its pickup circuit passing from terminal B, through contacts I5 and I6 of relays ITES and CP, respectively, and the winding of relay IDS to terminal N. Relay IDS, upon becoming energized, closes its own stick circuit passing from terminal B, through'contact is of relay ID, contact 23 of relay IDS, and the winding of relay IDS to terminal N.

Relay IDS, upon becoming energized, completes a circuit for energizing winding CX, this circuit passing from terminal B, through the front point of contact 5 of relay iDS, and winding CX of relay 'KX to terminal N. Upon the lapse of a brief period of time after relay C? becomes deenergized, relay CRP, which is controlled by relay 0?, and Whiuh is arranged to be slow releasing, permits it; contact 2i to close, so that relay ID then becomes energized by a circuit passing from terminal B, through contact M of relay CRP, and the winding of relay ID to terminal N.

In the proportionin of parts which I have assumed for an example of operation of apparatus embodying my invention, contact 25 of relay CR? becomes closed about 1 second after relay CR becomes deenergized. Relay ID, upon becoming energized, opens its contact Is in the stick circuit for relay IDS, causing relay IDS to become deenergized. On account of relay CR being deenergized, contact CR4, in the circuit first traced for winding CX of relay KX, is now open, so that winding CX becomes deenergized.

Highway crossing signal G, therefore, becomes operated by its circuit passing from terminal B, through contact 22 of winding CX, and the mechanism of signal G to terminal N.. Since it re quires 21 seconds for a train moving at a speed of 120 miles per hour to travel 3700 feet, and since relay ID does not become energized until 1 second after the train has entered section C, it follows that signal G will be operated for seconds be fore the train reaches the intersection of the railway with highway 1-1.

If, instead of traveling through section '1' at a speed of 120 miles per hour, the train moves at a speed between 80 and 120 miles per hour such, for example, as 95 miles per hour, the operation of the apparatus would be as just described for the train moving at 120 miles per hour before the train entered section C. The only difference in the result would be that the train traveling 9-5 miles per hour instead of 120 miles per hour would require a few more seconds than 20 to reach the intersection of the railway and highway H after the operation of signal G has begun.

I. shall now assume that all parts of the apparatus are again in the normal condition, and that an eastbound train moves over section T at a speed between 60 and 80 miles per hour. Time element device ITE and relays iTES and IDS will then become energized as previously described. With the train traveling between 60 and 80 miles per hour time element device ZTE al o will close its contact I3 before the train enters section C. Pickup and stick circuits for relay il'lES will then be closed which will be similar to the pickup and stick circuits previously traced for relay l'IE S. Relay ZDS will then become energized by a pickup circuit which is similar to the circuit previously traced for relay EDS. A stick circuit for relay ZDS, similar to the circuit previously traced. for relay lDS, will then also become closed, so that now the front point of contact 6 of relay EDS will be closed in multiple with the front point of contact 5 of relay IDS in the circuit for energizing winding CX of relay KX.

When the train enters section C, causing re-- CR, CP, and CRP in turn to be deenergized, time element device 213E becomes energized by a circuit passing from terminal B, through contact 22 of relay CRP, and time element device to terminal N. After device iiDE has been energized seconds, its contact it closes a circuit for relay 21), this circuit passing from terminal B, through contact 24 of device ZDE. and the winding of relay 2D to terminal N.

Relay 2D, upon becoming energized, opens its contact l9, thereby deenergizing relay EDS. Re- IDS has already become deenergized as previously described, so that new contacts of relays i238 and EDS are bothv open at their f1 ont points, and since contact CPU-J is open on account of relay CR being deenergized, winding OK or relay KX now becomes deenergized and causes the operation of signal G to begin.

From the foregoing description, it follows that the starting of the operation of signal G is delayed for a period of 10 seconds because of the energization of relay EDS. Since the train is now operating at aspeedbetween 60 miles per hour, signal G will be operated for a few seconds more than 20 before the train arrives at the intersection of the railway and the highway H.

I have described the operation of the apparatus for a few typical train speeds. It is beli d that, in View of the foregoing description, it will be clear how the apparatus can be similarly arranged and operated for various other ranges of train speeds.

Although I have herein shown and described only two forms of apparatus embodying my invention, it is understood that various changes 7b ,modificationsmay be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, What I claim is:

1. In a control system fOI a highway crossing signal in which a railway track which intersects a highway is divided into a timing section and an operating section arranged so that a train approaching the intersection occupies first the timing section and then the operating section, the combination comprising, a plurality of time element devices for said timing section a given one of which closes a contact after it is energized a given measured period of time and each of the others of which closes a contact in a consecutively longer measured period of time after it is energized, a plurality of timing stick relays one for each of said time element devices, means controlled by each of said contacts for energizing the associated timing stick relay, means controlled by a train on said timing section for retaining each of said timing stick relays energized.

means for energizing each of said time element devices as soon as said timing section becomes occupied if the associated timing stick relay is deenergized, a plurality of signal stick relays one for each of said timing stick relays, a delay relay for each of said signal stick relays, means for energizing said delay relays one at a time in consecutively longer periods of time after said operating section becomes occupied, a pickup circuit for each of said signal stick relays each con trolled by a front contact of the associated timing stick relay and by trafiic conditions in said operating section, a stick circuit for each of said signal stick relays each controlled by a back contact of the associated delay relay, means for operating said crossing signal in response to occupancy of said operating section by a train, and means controlled by a front contact of each of said signal stick relays for at times d wi'ng operation of said crossing signal.

2. In a control system for a highway crossing signal in which a railway track which intersects a highway is divided into a timing section and an operating section arranged so that a train approaching the intersection occupies first the timing section and then the operating section, the combination comprising, a plurality of time element devices each of which has a contact which becomes closed upon the lapse of a measured period of time after its time element device becomes energized and the measured period of time for each of said time element devices being of different length from that for each of the other time element devices, means for energizing said time element devices simultaneously when a. train enters said timing section, a signal stick relay for each of said time element devices, a track circuit for said operating section including a track relay, a pickup circuit for each of said signal stick relays each controlled by the contact of its time element device and by said track relay, a plurality of delay relays one for each of said signal stick relays, means for energizing said delay relays one at a time in consecutively longer periods of time after a train enters said operating section, a stick circuit for each of said signal stick relays each controlled by a back contact of its de ay relay, and means controlled by said signal stick relays and by said track relay for controlling said crossing signal.

3. In a control system for a highway crossing signal in which a railway track which intersects a highway is divided into a timing section and an operating section arranged so that a train approaching the intersection occupies first the timing section and then the operating section, the combination comprising, a plurality of time element devices each of which has a normally open contact and is constructed so that when said time element devices become energized simultaneously said contacts become closed consecutively upon the lapse of corresponding measured periods of time, means for energizing said time element devices simultaneously in response to a train entering said timing section, a plurality of delay relays each of which has a normally closed contact and is controlled in response to a train entering said operating section so that said contacts become opened consecutively upon the lapse of corresponding measured periods of time, a track circuit for said operating section including a track relay, a plurality of signal stick relays, a pickup circuit for each of said signal stick relays each controlled by one of said normally open contacts and by a front contact of said track relay, 9, stick circuit for each of said signal stick relays each controlled by the back contact of a corresponding one of said delay relays, and means controlled by said signal stick relays and by said track relay for controlling said crossing signal.

4. In a control system for a highway crossing signal in which a railway track which intersects a highway is divided into a timing section and an operating section arranged so that a train approaching the intersection occupies first the timing section and then the operating section, the combination comprising, a time element device, a timing stick relay, means controlled by a train on said timing section and by a back contact of said timing stick relay for energizing said time element device, a pickup circuit for said timing stick relay controlled by said time element device, a stick circuit for said timing stick relay controlled by a train on said timing section, a track circuit for said operating section including atrack relay, a slow release relay controlled by a front contact of said track relay, a second slow release relay controlled by a front contact of said first slow release relay, a signal stick relay, a delay relay controlled by a back contact of said second slow release relay, a pickup circuit for said signal stick relay controlled by front contacts of said timing stick and first slow release relays, a stick circuit for said signal stick relay controlled by a back contact of said delay relay, and means controlled by said signal stick relay and by said track relay for controlling said highway crossing signal.

5. In a control system for a highway crossing signal in wh ch a railway track which intersects a highway is divided into a timing section and an operating section arranged so that a train approaching the intersection occupies first the timing section and then the operating section, the combination comprising, a time element contact controlled to become closed upon the lapse of a measured period of time after said timing section becomes occupizd, a normally energized slow release relay controlled to become deenergized when said operating section becomes occupied, a second slow release relay controlled by a front contact of said first slow release relay, a signal stick relay, a pickup circuit for said signal stick relay controlled by said time element contact and by a front contact of said first slow release relay, a stick circuit for said signal stick relay controlled by a back contact of said second slow release relay, a control circuit for said highway crossing signal controlled by a back contact of said signal stick relay if said operating section is clear, and a second control circuit for highway crossing signal controlled by a front contact of said signal stick relay.

8. In a control system for a highway crossing signal in which a railway track which intersects a highway is divided into a timing section and an operating section arranged so that a train approaching the intersection occupies first the timing section and then the operating section, the combination comprising, a time element contact controlled to become closed upon the lapse of a measured period of time after said timing section becomes occupied, a second time element contact controlled to become closed upon the lapse of a further measured period of time after said first time element contact becomes closed, a

relay, a pickup circuit for said first signal stick relay controlled by said first time element contact and by a front contact of said first slow release relay, a stick circuit for said first signal stick relay controlled by a back contact of said second slow release relay, a pickup circuit for said second signal stick relay controlled by said second time element contact and by a front contact of said first slow release relay, a third time element contact controlled by a back contact of said second slow release relay, a stick circuit for said second signal stick relay controlled by said third time element contact, means responsive to a train on said operating section for operating said highway crossing signal, and means controlled by said firstand second signal stick relays for at times delaying operation of said highway crossing signal when a train enters said operating section.

7. In a control system for a highway crossing signal in which a railway track which intersects a highway is divided into a timing section and an operating section arranged so that a train approaching the intersection occupies first the timing section and then the operating section, the combination comprising, 'a first and a sec- 0nd and a third time element contact controlled to become closed upon the lapse of a measured period of time after said timing section becomes occupied and upon the lapse of a further meas ured period of time and upon the lapse of a still further measured period of time respectively, a normally energized slow release relay controlled to become deenergized in response to a train entering said operating section, a second slow release relay controlled by a front contact of said first slow release relay, a first and a second and a third signal stick relay, a pickup circuit for said first signal stick relay controlled by said first time element contact and by a front contact of said first slow release relay, a stick circuit for said first signal stick relay controlled by a back contact of said second slow release relay, a fourth time element contact controlled to become closed upon the lapse of a measured period of time after a back contact of said second slow release relay becomes closed, a fifth time element contact controlled to become closed upon the lapse of a further measured period of time after a back contact of said second slow release relay becomes closed, a pickup circuit for each of said second and third signal stick relays controlled by said second and third time element contacts respectively and by front contacts of saidfirst slow release relay, a stick circuit for each of said MYRL R. DOUGLASS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,933,781 Williamson Nov. 7, 1933 2,030,532 Parkinson Feb. 11, 1936 

